SUMMARY Disorders of heart rhythm are the leading causes of sudden death and stroke. Progress in elucidating molecular, cellular and systems level mechanisms has promoted new concepts that have guided the development of more effective diagnostic and treatment strategies. However, cardiac arrhythmias remain major causes of morbidity and mortality throughout the world, and the need to push the boundaries of basic science discovery, which fuels translation, has never been more urgent. The 2019 Gordon Research Conference (GRC) on Cardiac Arrhythmia Mechanisms seeks to catalyze scientific advances to remedy this recalcitrant public health concern by assembling a cross-disciplinary program to inspire and drive the field by emphasizing multiscale challenges in understanding arrhythmia biology, highlighting emerging multidisciplinary investigational approaches, and featuring emerging therapeutic paradigms. This established biennial conference is widely regarded as the premier forum in which cutting edge concepts and new observations on mechanisms and treatment of cardiac rhythm disorders are presented. The Conference will bring together an international group of experts and trainees in many relevant fields, including genetics, basic electrophysiology, structural biology, biophysics, biomedical engineering, computer science, and clinical cardiology to interact in an informal atmosphere and share ideas about the mechanisms underlying normal and abnormal heart rhythms, including the causes of sudden cardiac death and stroke. The program includes current and emerging thought leaders in arrhythmia biology, investigators from complementary scientific disciplines, trainees and new investigators with promising careers. An objective of the Conference is to provide a forum for investigators ? junior, mid-level and senior ? to engage in focused discussion on the latest advances in the field of cardiac arrhythmia mechanisms, to bridge the gap between basic science and clinical applications, to stimulate new areas for collaboration, to promote collegiality and information sharing. The Conference will inspire and foster the career development of trainees by supporting an associated Gordon Research Seminar (GRS) at which trainees present their research findings and engage in panel discussions with mentors on matters of career pathways and professional development. A keynote address emphasizing the importance of scientific rigor and reproducibility in science will be featured at the GRS. We also plan an afternoon GRC Power Hour to discuss challenges women face in science and to promote the professional growth of women. The goals of this Conference are closely aligned with the mission of the NHLBI.